Crate hjkl_buffer 

hjkl-buffer

Rope-backed text buffer with vim-shaped semantics: charwise/linewise/ blockwise selection, motions matching vim edge cases (no h wrap, $ clamp, sticky col on j/k), folds, viewport, and search.

Extracted from sqeel-buffer with full git history. See MIGRATION.md for the roadmap and stability contract.

Features

• ratatui (off by default): enables the [render] module with a direct cell-write ratatui::widgets::Widget impl for Buffer.

Structs

Buffer

In-memory text buffer + cursor + viewport + per-row span cache.

BufferView

Render-time wrapper around &Buffer that carries the optional Selection + a StyleResolver. Created per draw, dropped when the frame is done — cheap, holds only refs.

Fold

Gutter

Configuration for the line-number gutter rendered to the left of the text area. width is the total cell count reserved (including any trailing spacer); the renderer right-aligns the 1-based row number into the leftmost width - 1 cells.

Position

A (row, col) location inside a crate::Buffer.

Sign

Single-cell marker painted into the leftmost gutter column for a document row. Used by hosts to surface LSP diagnostics, git diff signs, etc. Higher priority wins when multiple signs land on the same row.

Span

One styled byte range on a buffer row.

Viewport

Where the buffer is scrolled to and how big the visible area is.

Enums

Edit

One unit of buffer mutation. Constructed by the caller (vim engine, ex command, …) and handed to Buffer::apply_edit.

MotionKind

Granularity of a delete; preserved through undo so a linewise delete doesn’t come back as a charwise one.

Selection

First-class vim selection. Each variant carries the kind directly rather than relying on a single char-range primitive with separate “treat as line / block” overlays — that’s the whole point of owning the buffer model. Anchor is where the user pressed v / V / Ctrl-V; head moves with the cursor and is updated via Selection::extend_to.

Wrap

Soft-wrap mode controlling how doc rows wider than the text area turn into multiple visual rows. Default is Wrap::None — every doc row is exactly one screen row and top_col clips the left side, mirroring vim’s set nowrap default for sqeel today.

Traits

StyleResolver

Resolves an opaque crate::Span::style id to a real ratatui style. The buffer doesn’t know about colours; the host (sqeel-vim or any future user) keeps a lookup table.

Type Aliases

RowSpan

Bounds of a selection on a particular row, expressed as inclusive char-column range. None means the row is outside the selection. Some((0, usize::MAX)) is the convention for “whole row” — the renderer caps it at the row’s actual length.